This application is based on Patent Application No. 2000-302721 filed Oct. 2, 2000 in Japan, the content of which is incorporated hereinto by reference.
1. Field of the Invention
The present invention relates to a liquid ejection head for ejecting a liquid, a head cartridge provided with the same, and a liquid ejection apparatus.
2. Description of the Related Art
An ink-jet printing apparatus is equipped with an ink-jet print-head as a liquid ejection print head. As the ink-jet print head, there is generally known an edge shooter type or a side shooter type ink-jet print head.
The side shooter type ink-jet print head, for example, as shown in Japanese Patent Laid-open Publication No. 8446/1994, or FIG. 11 and FIG. 12, comprises a tank 8 storing a predetermined ink, and an orifice plate 2 having a plurality of ink ejection openings 2ai and 2bi (i=1 to n, n being an integer) for ejecting ink from the tank 8, a printing element substrate 4 joined with the orifice plate 2 and having heaters (heat generation resistors) 4ai and 4bi (i=1 to n, n being an integer) as printing elements opposing the respective ink ejection openings 2ai and 2bi, and a connection member 6 for connecting the orifice plate 2 and the printing element substrate 4 and the tank 8.
Such an ink jet print head is, for example, connectedly disposed with a predetermined height difference relative to an ink supplier for supplying ink to its tank 8, so that its internal pressure is a predetermined negative pressure.
The tank 8, as shown in FIG. 12, has an opening 8a for communicating the storage for storing ink 12 with a communicating passage 6a of the connection member 6. The communicating passage 6a of the connection member 6 communicates with a common liquid chamber 2e in the orifice plate 2 through an ink supply opening 4d at a nearly central part of the printing element substrate 4. Therefore, a supply passage 10 is formed of the opening 8a, communicating passage 6a and the ink supply opening 4d. With this construction, ink 12 in the tank 8 is supplied to the common liquid chamber 2e through the supply passage 10 along the direction shown by the arrow.
The ink supplied to the common liquid chamber 2e is supplied to each branched supply passage formed between the orifice plate 2 and the printing element substrate 4. At the part opposing the ink ejection openings 2ai and 2bi in the respective branched supply passages, heaters 4ai and 4bi are formed, respectively.
The respective heaters 4ai and 4bi are controlled by drive pulse signals according to an image data representing an image to be printed from a controller (not shown). By this operation, when the respective heaters 4ai and 4bi are operative, the ink 12 is heated by the respective heaters 4ai and 4bi to be ink droplets ID by a film boiling phenomenon which are ejected to a recording surface of the printing medium.
Further, in the ink-jet print head, instead of the operation that the ink 12 is supplied to each of the respective branched supply passages of the printing element substrate 4 through the ink supply opening 4d at its nearly central part as described above, for example, as shown in Japanese Patent Laid-open Publication No. 305592/1998 and FIG. 13, it is proposed that ink is supplied from both end sides of the printing element substrate to each branched supply passage.
Referring to FIG. 13, the ink-jet print head comprises a tank 14 for storing ink 22, a substrate support member 20 disposed in the tank 14 for supporting the printing element substrate 18, and an orifice plate 16 having a plurality of ejection openings 16ai and 16bi (i=1 to n, n being an integer) opposing the respective heater 18ai and 18bi of the printing element substrate 18 and joined to the tank 14.
Between the heaters 18ai and 18bi of the printing element substrate 18 and the inside surface of surface on which the ejection openings 16ai and 16bi of the orifice plate 16 are formed, branched supply passages are formed which conduct the ink 22 from both end sides of the printing element substrate 18 to the respective heaters 18ai and 18bi. With this construction, similar to as described above, when the respective heaters 18ai and 18bi are operative, the ink 22 is ejected in the form of ink droplets ID through the ejection openings 16ai and 16bi.
When inks of a plurality of colors are ejected using a print head as shown in FIG. 11, the inside of the above tank 8 is partitioned to store inks of respective colors, for example, Yellow Y, Magenta M, and Cyan C, further, in the ink ejection openings 2ai and 2bi in the orifice plate 2 and in the heaters 4ai and 4bi of the printing element substrate 4, areas 2Y, 2M and 2C are previously set which are used according to Yellow Y, Magenta M, and Cyan C.
In such a case, when the print head is moved along the direction shown by arrow S shown in FIG. 11 to perform printing operation with inks of respective colors, since the printing width along the arrangement direction of the ejection openings printed per one movement is decreased as compared to a case of ejecting ink of a single color, resulting in a reduction of a so-called throughput.
In such a case, for example, to prevent the reduction of the throughput, it is considered that three orifice plates 2 and printing element substrates 4 are provided in parallel. However, as a result thereof the print head is increased in size against the requirement of downsizing.
Further, when inks of a plurality of different colors are used in the constructions of the orifice plate and printing element substrate as shown FIG. 12 and FIG. 13, it is difficult in design to set flow rates flowing in the respective ejection opening arrays according to ejection amounts of respective inks.
In view of the above problems, it is an object of the present invention to provide a liquid ejection head for ejecting a liquid, a head cartridge provided therewith and a liquid ejection apparatus which are capable of setting respective flow rates of inks flowing in respective ejection opening arrays according to ejection amounts of respective inks without reducing a so-called throughput.
In accordance with the present invention which attains the above object, there is provided a liquid ejection head comprising a liquid ejection opening formation section in which a first group of liquid ejection openings and a second group of liquid ejection openings for ejecting a liquid are formed, an element substrate having a plurality of energy generation elements formed in opposition to the first group of liquid ejection openings and the second group of liquid ejection openings for generating energy utilized to eject a liquid from the first group of liquid ejection openings and the second group of liquid ejection openings, a first liquid supply passage formed between one end of the element substrate and an inner wall of the liquid ejection opening formation section for supplying a liquid stored in a first liquid supply source onto the energy generation element opposing the first group of liquid ejection openings, and a second liquid supply passage formed independently of the first liquid supply passage between the other end at the opposite side to one end of the element substrate and an inner wall of the liquid ejection opening formation section for supplying a liquid stored in a second liquid supply source independent of the first liquid supply source onto the energy generation element opposing the second group of liquid ejection openings.
Further, the liquid ejection head according to the present invention comprises a liquid ejection opening formation section in which a first group of liquid ejection openings and a second group of liquid ejection openings for ejecting a liquid are formed, a printing element substrate having printing elements formed in opposition to the first group of liquid ejection openings and the second group of liquid ejection openings of the liquid ejection opening formation section for ejecting a liquid through the first group of liquid ejection openings and the second group of liquid ejection openings, a liquid supply passage formed inside the printing element substrate for supplying the liquid from a liquid supply source to a printing element opposing the first group of liquid ejection openings in the printing element substrate, and a liquid supply passage group comprising a plurality of liquid supply passages formed inside the printing element substrate independent of the first liquid supply passage for individually supplying liquids from a plurality of liquid supply sources to printing elements opposing the second group of liquid ejection openings in the printing element substrate.
The liquid ejection apparatus according to the present invention comprises the above liquid ejection head, moving means for moving the liquid ejection head in opposition to a recording surface of the printing medium, and a controller for controlling the printing operation of the liquid ejection head and operation of the moving means.
As can be seen from the above description, according to the liquid ejection head of the present invention, and the head cartridge provided with the same, and the liquid ejection. apparatus, since the flow passage cross sectional area of the first liquid supply passage and the flow passage cross sectional area of the second liquid supply passage are set according to ejection amounts respectively of the first liquid ejection opening array and the second liquid ejection opening array, flow rates flowing in the respective ejection opening arrays can be set without reducing a so-called throughput and according to respective ink ejection amounts.